12 Actors Who Massively Transformed Themselves for a Role

by DEBORAH DAY Last Updated: Sep 13, 2017

Deborah Day

Deborah Day is a lifestyle and entertainment writer and editor. Former editor in chief of Maxim.com and executive editor of Premiere.com, she has been published on EW.com, TheWrap.com, Yahoo.com, LAmag.com and other media sites, as well as in Maxim, Interview and Time Out NY magazines.

Ever since Robert De Niro piled on 60 pounds to play boxer Jake La Motta in 1980’s “Raging Bull,” Hollywood’s hottest talents have followed his lead, enduring extreme weight fluctuations for the sake of a plum role. And their risks have been frequently rewarded with Academy Awards, like Natalie Portman for “Black Swan” and Matthew McConaughey for “Dallas Buyers Club.” But there are potential dangers in the practice. “Yo-yo dieting -- going up and down in weight -- can cause permanent damage to the body, like a whole slew of stresses to the heart and a weakened immune system,” says LIVESTRONG.COM’s Kelly Plowe, a registered dietitian and certified sports dietitian. There’s also the more immediate mental impact that comes from rapid weight loss. “Your brain runs on carbs, so if you aren’t getting enough of those, you’re not going to be running on all cylinders,” says Plowe. “Also, crash dieting can mess with your electrolyte balance, even more so if you’re using diuretics, laxatives, purging, etc. This puts you at risk of feeling dizzy or even fainting, and it can cause muscle cramps or significant issues with your heart.” Check out 12 celebrities who risked all this for their roles.

1 CHRIS HEMSWORTH, “IN THE HEART OF THE SEA”

Hemsworth, who plays Thor in Marvel’s superhero juggernaut, went on a 500-calorie-a-day diet to appear as seaman Owen Chase in the film about a vengeful fish preying on a whaling ship in the early 1800s. In November 2015 Hemsworth tweeted an image of his dramatic weight loss ahead the film’s December release, writing: “Just tried a new diet/training program called Lost at Sea. Wouldn’t recommend it.” Director Ron Howard explained the process and the need to EW: “They had to work out every day, even on shooting day. They needed to keep burning the calories, and we also needed that sinewy strength that was more of that era, as opposed to a kind of cut, buff look.” After he’s done filming Thor movies, he told MTV that he craves not eating: “I basically overfeed on protein -- endless amounts of chicken breasts, steak and fish and vegetables, brown rice. When I’m finished shooting, it’s just ‘Enough with the weightlifting and the eating.’”

2 JAKE GYLLENHAAL, “SOUTHPAW”

After slimming down to 147 pounds to play creepy videographer Lou Bloom in 2014’s “Nightcrawler,” a year later the actor put on 28 pounds to play middleweight champ Billy Hope in director Antoine Fuqua’s boxing film. In addition to putting the actor through rigorous boxing drills, Los Angeles coach and Lb4Lb Boxing Gym owner Terry Claybon had Gyllenhaal lifting and flipping a 250-pound tractor tire 20 times a day and pounding it with a sledgehammer. “We trained really hard every day, all day,” the actor told Men’s Journal, “and you can eat a lot when you’re in that mode. It was always high-protein. I remember eating a lot of Chipotle.”

3 CHRIS PRATT, “GUARDIANS OF THE GALAXY”

Known for his soft underbelly as Andy Dwyer on NBC’s “Parks and Recreation,” the actor lost 60 pounds in six months to play Star Lord Peter Quill in 2014’s blockbuster Marvel movie. Pratt, who was almost 300 pounds at the time of his audition, told Men’s Fitness how he dropped the weight: “Three or four hours a day of just consistent, ass-kicking hard work.” That hard work included sessions of P90X, running, swimming, boxing and kickboxing, according to the magazine, supervised by personal trainer Duffy Gaver and nutritionist Phil Goglia, who bumped up the actor’s caloric intake to 4,000 calories a day and recommended he drink one ounce of water for every pound he weighed. Pratt posted a photo of his newly toned physique on Instagram in 2013, writing, “Six months no beer. #GOTG Kinda douchey to post this but my brother made me.”

4 HILARY SWANK, “BOYS DON’T CRY”

Swank lost an extreme amount of body fat for her 1999 performance as real-life murder victim Brandon Teena, for which she won an Academy Award. “When you change your weight it has an impact on your health,” the actress told The Mail on Sunday. “For ‘Boys Don’t Cry’ I went down to 9 percent body fat so that I would look kind of sunken, but I was 24 and I bounced right back.” However, she later got mercury poisoning from eating excessive amounts of fish to gain 19 pounds of muscle for her role as female boxer Maggie Fitzgerald for “Million Dollar Baby,” which netted her a second best actress Oscar.

5 MATTHEW MCCONAUGHEY, “DALLAS BUYERS CLUB”

The 2013 role of HIV-positive Ron Woodroof garnered McConaughey a best actor Academy Award, and the actor lost 47 pounds to do it. “I did it in as healthy a way as I found possible,” he told the BBC. “I met with a nutritionist. I gave myself four months to lose the weight. I had my programmed meals, lost 3.5 pounds a week -- like clockwork -- and got down to my desired weight, which turned out to be 47 pounds lighter.” His transformation into Woodroof stood in stark contrast to his chiseled appearance in 2012’s “Magic Mike.” Celebrity trainer Gunnar Peterson, who worked with the actor on several films, told Bodybuilding that those “Magic Mike” abs are the result of “a ton of work in rotation. We’d do leg raises at an angle or leg raises at an angle with resistance. We also did a lot of planks.”

6 JARED LETO, “DALLAS BUYERS CLUB”

Leto has reinvented his physique for the screen several times. For director Darren Aronofsky’s “Requiem for a Dream” in 2000, he shed 28 pounds of his 153-pound frame to play drug addict Harry Goldfarb. “I didn’t eat meals for weeks,” he told Jam! Showbiz while promoting the film. “I just nibbled, and nothing bigger than a little piece, not even a mouthful.” He then gained 60 pounds to appear as Mark Chapman, the deranged fan who killed former Beatle John Lennon, in “Chapter 27.” Leto told The Daily News in 2008, “Toward the end of the shoot, one of the glaring issues was the pain I had with my feet. I couldn’t walk for long distances; I had a wheelchair because it was so painful. My body was in shock from the amount of weight I gained.” The actor then bested his “Requiem” effort when he appeared opposite McConaughey in 2013’s “Dallas Buyers Club,” losing more than 40 pounds for the role of transgender HIV-sufferer Rayon. “I lost around 40 pounds, and then I stopped counting,” Leto told The Guardian. “For me, it was about how it made me feel, how it made other people treat me.”

7 CHARLIZE THERON, “MONSTER”

To play serial killer Aileen Wuornos in 2003, the normally svelte actress and model gained 30 pounds eating junk food. “I first began stuffing myself with Krispy Kreme doughnuts, but after a while I got sick of them,” she told Guerilla Traveler. “I love potato chips, so that was a good thing for me. I’m a salty girl so I had my secret stash with me of potato chips at all times. I never got tired of potato chips. I could live off potato chips!” Her extreme measures resulted in a best actress Oscar. A much slimmer Theron later appeared in body-hugging costumes in 2005 sci-fi film “Aeon Flux.”

8 CHRISTIAN BALE, “AMERICAN HUSTLE”

The man who would be Batman shed 63 pounds to appear as insomniac lathe operator Trevor Reznik in 2004’s “The Machinist,” dropping the 6-foot actor’s weight to a scant 122 pounds. “I had been to a nutritionist, and when I had got down to what she had told me was a healthy weight, I just went, ‘You know what? I can go more than this. I can keep going.’ So I lost another 20 pounds below what she said I should stop at,” Bale told the BBC. He then bulked up to play the Caped Crusader in 2005’s “Batman Begins,” dropped pounds again to play former boxer and drug addict Dicky Eklund for 2011’s “The Fighter” -- a role that snagged him a supporting actor Oscar. He then cultivated a robust “dad bod” for the role of Irving Rosenfeld in director David O. Russell’s 2013 film “American Hustle.” The actor must have hit his limit, however; in 2016, he dropped out of Michael Mann’s biopic of Enzo Ferrari, citing health concerns over the weight gain needed to play the carmaker.

9 RENéE ZELLWEGER, “BRIDGET JONES’S DIARY”

Zellweger revisits pudgy British singleton Bridget Jones in 2016 for the baby edition of the trio of films. But while the actress put on nearly 30 pounds for 2001’s “Bridget Jones’s Diary” and its 2004 sequel “Bridget Jones: The Edge of Reason,” she’s noticeably slimmer for “Bridget Jones’s Baby.” “We all really loved the notion that Bridget, 15 years on, had finally reached her ideal weight -- somewhere between a UK size 10 or 12 -- but still hadn’t solved any of her issues about love and loneliness,” director Sharon Maguire told Entertainment Weekly. Dailymail.co.uk reported the actress as saying, “For two days it’s bliss and then you’re full, OK? Then after a week your glucose levels are going crazy. You’re up and down and all over the place. It doesn’t feel good.” Scrutiny of the actress flip-flopped for her role as lethal bombshell Roxy Hart in the 2002 musical “Chicago,” which saw her drop the Bridget weight and then some.

10 50 CENT, “ALL THINGS FALL APART”

Inspired by a friend who had died of the condition, the rapper took on the role of cancer-stricken football player Deon, trimming his normally muscular frame down to 160 pounds with three-hour treadmill walks and a harsh diet. “I was on liquids. I started with the lemon and cayenne…. After the first week, it was too tough for me to stick with that,” he said about his diet on NBC’s “Today” show in 2010. “I was doing cardio training. My energy levels started to drop as I started to lose some of the weight, so I was, like, speed walking.” Later, while promoting his fitness program “Formula 50,” the actor and executive producer of Starz’ series “Power” wrote about the experience: “Scaling down from my usual 215 would mean running 15 miles not once but twice a day and surviving on a liquid diet for 10 weeks. Folks in my inner circle said I was crazy.”

11& 12. NATALIE PORTMAN AND MILA KUNIS, “BLACK SWAN”

The 5'3" actresses dropped around 25 pounds each for the 2010 Darren Aronofsky-directed thriller set in New York City’s cutthroat ballet world. “There were some nights that I thought I literally was going to die,” Portman said of the experience to Entertainment Weekly. “It was the first time I understood how you could get so wrapped up in a role that it could sort of take you down.” Kunis described the grueling process to Daily Mail Online: “I trained four hours a day, seven days a week, for seven months. Aesthetically, I had to look like a ballerina and hold myself like one. By the end, I was 95 pounds. All you saw was bone. It looked disgusting, but in photographs and on film it looked amazing. It took me five months to lose the weight, but just five days to gain it all back.”